1 files changed, 62 insertions, 18 deletions

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 2754f3069738..f2db99031e2f 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -577,6 +577,8 @@ static int vhost_vdpa_map(struct vhost_vdpa *v,
 
 	if (r)
 		vhost_iotlb_del_range(dev->iotlb, iova, iova + size - 1);
+	else
+		atomic64_add(size >> PAGE_SHIFT, &dev->mm->pinned_vm);
 
 	return r;
 }
@@ -608,8 +610,9 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
 	unsigned long list_size = PAGE_SIZE / sizeof(struct page *);
 	unsigned int gup_flags = FOLL_LONGTERM;
 	unsigned long npages, cur_base, map_pfn, last_pfn = 0;
-	unsigned long locked, lock_limit, pinned, i;
+	unsigned long lock_limit, sz2pin, nchunks, i;
 	u64 iova = msg->iova;
+	long pinned;
 	int ret = 0;
 
 	if (msg->iova < v->range.first ||
@@ -620,6 +623,7 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
 				    msg->iova + msg->size - 1))
 		return -EEXIST;
 
+	/* Limit the use of memory for bookkeeping */
 	page_list = (struct page **) __get_free_page(GFP_KERNEL);
 	if (!page_list)
 		return -ENOMEM;
@@ -628,52 +632,75 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
 		gup_flags |= FOLL_WRITE;
 
 	npages = PAGE_ALIGN(msg->size + (iova & ~PAGE_MASK)) >> PAGE_SHIFT;
-	if (!npages)
-		return -EINVAL;
+	if (!npages) {
+		ret = -EINVAL;
+		goto free;
+	}
 
 	mmap_read_lock(dev->mm);
 
-	locked = atomic64_add_return(npages, &dev->mm->pinned_vm);
 	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
-
-	if (locked > lock_limit) {
+	if (npages + atomic64_read(&dev->mm->pinned_vm) > lock_limit) {
 		ret = -ENOMEM;
-		goto out;
+		goto unlock;
 	}
 
 	cur_base = msg->uaddr & PAGE_MASK;
 	iova &= PAGE_MASK;
+	nchunks = 0;
 
 	while (npages) {
-		pinned = min_t(unsigned long, npages, list_size);
-		ret = pin_user_pages(cur_base, pinned,
-				     gup_flags, page_list, NULL);
-		if (ret != pinned)
+		sz2pin = min_t(unsigned long, npages, list_size);
+		pinned = pin_user_pages(cur_base, sz2pin,
+					gup_flags, page_list, NULL);
+		if (sz2pin != pinned) {
+			if (pinned < 0) {
+				ret = pinned;
+			} else {
+				unpin_user_pages(page_list, pinned);
+				ret = -ENOMEM;
+			}
 			goto out;
+		}
+		nchunks++;
 
 		if (!last_pfn)
 			map_pfn = page_to_pfn(page_list[0]);
 
-		for (i = 0; i < ret; i++) {
+		for (i = 0; i < pinned; i++) {
 			unsigned long this_pfn = page_to_pfn(page_list[i]);
 			u64 csize;
 
 			if (last_pfn && (this_pfn != last_pfn + 1)) {
 				/* Pin a contiguous chunk of memory */
 				csize = (last_pfn - map_pfn + 1) << PAGE_SHIFT;
-				if (vhost_vdpa_map(v, iova, csize,
-						   map_pfn << PAGE_SHIFT,
-						   msg->perm))
+				ret = vhost_vdpa_map(v, iova, csize,
+						     map_pfn << PAGE_SHIFT,
+						     msg->perm);
+				if (ret) {
+					/*
+					 * Unpin the pages that are left unmapped
+					 * from this point on in the current
+					 * page_list. The remaining outstanding
+					 * ones which may stride across several
+					 * chunks will be covered in the common
+					 * error path subsequently.
+					 */
+					unpin_user_pages(&page_list[i],
+							 pinned - i);
 					goto out;
+				}
+
 				map_pfn = this_pfn;
 				iova += csize;
+				nchunks = 0;
 			}
 
 			last_pfn = this_pfn;
 		}
 
-		cur_base += ret << PAGE_SHIFT;
-		npages -= ret;
+		cur_base += pinned << PAGE_SHIFT;
+		npages -= pinned;
 	}
 
 	/* Pin the rest chunk */
@@ -681,10 +708,27 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
 			     map_pfn << PAGE_SHIFT, msg->perm);
 out:
 	if (ret) {
+		if (nchunks) {
+			unsigned long pfn;
+
+			/*
+			 * Unpin the outstanding pages which are yet to be
+			 * mapped but haven't due to vdpa_map() or
+			 * pin_user_pages() failure.
+			 *
+			 * Mapped pages are accounted in vdpa_map(), hence
+			 * the corresponding unpinning will be handled by
+			 * vdpa_unmap().
+			 */
+			WARN_ON(!last_pfn);
+			for (pfn = map_pfn; pfn <= last_pfn; pfn++)
+				unpin_user_page(pfn_to_page(pfn));
+		}
 		vhost_vdpa_unmap(v, msg->iova, msg->size);
-		atomic64_sub(npages, &dev->mm->pinned_vm);
 	}
+unlock:
 	mmap_read_unlock(dev->mm);
+free:
 	free_page((unsigned long)page_list);
 	return ret;
 }